Kinetics driving thin-film deposition in dielectric barrier discharges using a direct liquid injector operated in a pulsed regime

Abstract

This work investigates the effects of process parameters on thin-film deposition by direct liquid injection in a low-frequency dielectric barrier discharge. The precursor, hexamethyldisiloxane, is introduced as micrometer-size liquid droplets with nitrogen carrier gas in a pulsed mode and the discharge is produced at atmospheric pressure in a pulsed regime. No significant deposit is observed during plasma-off time and outside the discharge region. Despite the pulsed injection, this reveals that the precursor content in the plasma zone remains constant over much longer time scales and that thin-film deposition results from droplets charging and their transport towards the dielectrics by the low-frequency electric field. Over the range of experimental conditions investigated, it is found that pulsed, aerosol-assisted plasma deposition is limited by the amount of energy provided to precursor droplets, and not by precursor insufficiency.